This proposal aims to study mammalian transcription factors involved in the early stages of adipocyte differentiation. A Drosophila gene, serpent, has been demonstrated to be involved in fruit fly fat body development. We investigated if the mammalian homologues of serpent, the GATA family of transcription factors, are involved in the adipogenesis program. Out of six members of this family, we have observed that GATA-2 is expressed in both white and brown adipose tissues and GATA-3 is expressed in white, but not in brown adipose tissue. GATA-2 and GATA-3 expression was also detected in 3T3-F442A preadipocytes and their expression is dramatically down regulated immediately after the induction of differentiation into adipocytes. Finally, both GATA-2 and GATA-3 expression is down regulated in the white adipose tissues of obese (ob/ob) mice. Based on these observations, I hypothesize that GATA transcription factors, GATA-2 and GATA-3 in specific, are potential preadipocyte markers and play an important role in adipogenesis. In this project, I propose to characterize the biological function of GATA factors in adipogenesis and elucidate the mechanisms through which GATA factors affect adipocyte differentiation. 1. To examine the expression of GATA factors in adipose tissue and during adipogenesis. 2. To investigate the biological effects of GATA factors on adipocyte differentiation. 3. To investigate the mechanism(s) by which GATA-2 and/or GATA-3 regulate the adipogenesis.